G.A. pilots are taught to stay on the ground when the weather briefing doesn't look good. That advice may be Politically Correct, but it doesn't cut the mustard if you use your airplane as a serious long-range transportation tool. The author has flown dozens of coast-to-coast trips by lightplane in all sorts of weather, and offers one experienced instrument pilot's perspective on how to deal with real-world weather.
January 27, 1998
decades ago, my primary flight instructor taught me that being a safe pilot meant staying
on the ground when the weather didn't look good. When I got my instrument rating a few
years later, my CFII cautioned me against flying when icing or thunderstorms were
Such advice may be okay for pilots who fly for recreation, but it's simply unrealistic
if you fly for business and use your airplane as a serious transportation tool. This is
doubly true if you fly transcontinental distances, as I do several times a year. It's
seldom possible to fly 2,000 nautical miles without having to traverse at least one major
Naturally, there are times when the weather is bad enough that staying on the ground is
the only prudent course. Even the airlines occasionally cancel flights due to weather. But
unless we can operate with a fairly high probability of getting where we need to go when
we need to be there, the airplane can't be counted on for serious business travel.
We've all heard the cliché: there are old pilots and bold pilots, but no old bold
pilots. Unfortunately, it's not that simple. Weather flying requires a certain measure of
boldness. The question is: how much is too much?
Obviously, what sort of weather we take on might be influenced by what kind of
equipment we're flying. Single or twin? Turbocharged or normally-aspirated? Boots? Hot
props? Stormscope? Weather radar?
But to be honest, I think equipment is
overrated. For twenty years and thousands of hours, I did serious long-distance weather
flying in a 1968 Cessna Skylane and later a 1972 Bellanca Super Viking — both
single-engine, normally-aspirated airplanes with no deicing or weather avoidance gear or
even dual vacuum pumps. The Skylane didn't even have an autopilot. For the last decade,
most of my trips have been flown in my 1979 Cessna T310R — a turbocharged twin approved
for flight into known icing conditions and with a Stormscope.
Yet I cannot recall a single trip flown in the 310 that would have been cancelled had I
been flying the Skylane or Viking. When I think about the scariest weather flying episodes
I've experienced over the past 30 years, it strikes me that they would have been scary
whether I was flying a Citabria or a Citation. I won't deny that flying more sophisticated
and capable equipment certainly contributes to my comfort level when tackling difficult
weather, and affects some weather-avoidance tactics — such as whether to fly above the
weather, below it or around it — but it doesn't influence my basic go/no-go decision very
What's more important to me are human factors considerations. Am I feeling fit and
rested, or fatigued? How about my instrument flying proficiency: curent and sharp, or
rusty? Do I really have the intestinal fortitude to handle a couple of hours of moderate
turbulence without losing my lunch? What is my inner voice saying?
Equally important, if not more so, is whether or not I'm carrying passengers. My wife,
for example, is a nervous flyer who is terrified of turbulence and has half the
"bladder endurance" that I do. I've frequently cancelled or delayed flights when
she was along that I'd have made without hesitation if I was flying alone. When I'm flying
with passengers that I don't know quite as well as my wife, I might have to interview each
one in some depth before deciding whether or not the flight can be made without
traumatizing them. (When flying in challenging weather, the last thing I want to deal with
is a cabin full of white knucklers.)
The Big Picture
To me, the most important part of briefing for a long flight is getting the big
picture. Am I flying from good weather to bad, or bad weather to good? (I much prefer the
latter.) What is the overall weather trend: deteriorating, improving, or steady-state?
Would the weather would be better if I waited a few hours, or checked into a hotel and
left first thing in the morning?
I find that it's hard to get the big picture from a
standard FSS or DUATS pilot weather briefing. My usual source of big-picture information
is The Weather Channel. I'll usually start keeping an eye on TWC for several days prior to
departing on a major trip. A picture is worth 1,000 words. I've even been known to choose
one hotel over another based on TWC availability when making reservations for a R.O.N.
Cable TV "superstations" are also great sources for regional weather
information. For example, WGN-Chicago provides exceptional weather graphics for the Great
Lakes area, and has TV meteorologists who really know the idiosyncrasies of the region's
weather. Other good regional weather sources on cable TV include KDVR-Denver,
KOMO-Seattle, KTLA-Los Angeles, and WWOR-New York, among others.
Over the past couple of years, I've started
to rely more and more on the Internet for getting the big picture. I carry my notebook
computer everywhere I go so I can access weather information on the World Wide Web, as
well as obtain briefings and file flight plans using DUATS. The weather graphics on the
Web are absolutely superb, and it's available on demand...no need to wait as with TV.
Here are a few of my favorite Internet weather sites. You might want to bookmark them
in your web browser for future reference. There are tons more on the AVweb weather page.
|| Radar, satellite, surface analysis, etc.
|| Univ. of Michigan
|| NEXRAD radar at major US cities
|| Purdue University
|| Wide range of weather graphics
|| The Weather Channel
|| Aviation weather graphics
|| USA Today
|| Weather for pilots
|| Regional, national, int'l weather maps
|| NCAR Aviation Page
|| IFR/VFR/MVFR conditions, PIREPs, wind/temp/moisture aloft, icing,
|| NOAA Aviation Weather Center
|| Numerous aviation weather products including experimental
"neural net" icing forecasts
By the time I obtain my preflight weather briefing, I already have a pretty good idea
of the big picture. As a general rule, I prefer to obtain my pre-flight briefing using
DUATS so that I can review the raw information myself without having it
"filtered" by an FSS briefer. I get particularly exasperated at briefers who try
to put their own "spin" on the weather, rather than just giving it to me
straight. (I just want to scream and hang up whenever I hear a briefer tell me "VFR
not recommended" when I call for an IFR briefing!)
An exception to this rule occurs when I'm worried about the weather at the departure
airport, because the briefer at the local FSS can sometimes offer worthwhile local weather
knowledge. Telephoning the FSS is also convenient for quick updates during fuel stops when
computer access is not available. But regardless of whether the briefing is by telephone
or computer, it's important to keep in mind some of the limitations of the aviation
weather forecasts it contains.
For one thing, forecasts tend to be pessimistic. Weather forecasting is an uncertain
business, and the forecasters who prepare aviation weather products have a natural
tendency to make worst-case predictions. Many FSS briefers tend to inject their own dose
of pessimism into their briefings. If there's one thing I've learned in three decades
of weather flying, it's that the weather is almost always better than forecast, seldom
worse. I can't count the number of times I've received a gloomy preflight briefing,
only to discover that the actual flight was a piece of cake.
Another important limitation of aviation forecasts is that they are based on
probabilities. Just because the forecast says rain or snow is likely over a large
multi-state region doesn't mean that it's going to rain or snow at any particular spot in
that region (such as your destination airport). In fact, it's not at all unusual to
fly across such an area without ever encountering adverse weather.
There are certain weather events that are nearly impossible to forecast with any
accuracy at all. Icing is foremost among these. As far as I'm concerned, standard icing
AIRMETs are almost worthless. The only source of trustworthy icing information in a
preflight weather briefing comes from PIREPs. One of my great frustrations is that pilots
aren't more conscientious about filing PIREPs when flying in areas where icing is
forecast...especially "negative icing" PIREPs (which is, after all, exactly what
other pilots need to know).
The new experimental "neural net" models for
forecasting icing conditions have considerable promise, however — you can check these out
on the NOAA Aviation Weather Center web site.
Forecasters do a better job with thunderstorms, but they still have a tough time
predicting exactly where or when the storms will develop, or whether they'll be readily
circumnavigable or not.
On the California coast (where I'm based), low stratus and fog frequently develops in
the evening and burns off in the morning. I find that forecasters do a pretty good job of
predicting whether or not fog will form, but they're often wrong about when it will
develop (sometimes by several hours one way or the other).
The bottom line is that I'm skeptical about aviation weather forecasts. In the absence
of "hard" information (such as PIREPs and current surface and radar reports),
I'm inclined to launch and take a look for myself...provided I'm sure that I have a
"solid gold out" in case things look grim.
Finally, it's important to recognize that the accuracy of aviation weather forecasts
deteriorates rapidly as they project further into the future. A terminal forecast may be
fairly accurate for the next couple of hours, but the prediction for six hours out should
be considered little more than an educated guess. If you're flying a 4 or 5 hour leg, it
doesn't make much sense to depend on a preflight briefing for the weather at your
destination, because that info will be at least 6 hours old by the time you arrive.
Consequently, it's important to keep close
tabs on the weather while you're enroute. One of the best ways to do that is to monitor
both Center and Flight Watch and listen to both sides of the conversations. It's
especially useful to hear pilots submitting PIREPs, because you can often tell as much
from their tone of voice as from the report itself. You're also likely to hear a lot of
stuff that never makes it onto the weather wire, like pilots requesting altitude changes
or weather deviations.
I also make a habit of keeping an eye on the clock and calling Flight Watch a few
minutes after the top of each hour to get an update on the destination weather. After a
few hours of these checkpoints, I have a real good feeling for the trend, and have plenty
of time to anticipate problems and formulate alternatives. For example, if I'm headed for
home after dark and worried if I can beat the fog, I'll keep close tabs on the hourly
temperature/dewpoint spread and get a pretty good idea of when the airport is likely to go
The NTSB has ruled that forecast icing conditions are considered to be "known
icing," which means in theory that most light planes are grounded whenever the
forecast calls for a chance of ice. Get real! If we stayed on the ground whenever ice was
forecast, we couldn't fly for 4 or 5 months out of the year in many portions of the
country. And so far as I can determine, the FAA has never pursued a volation against an
airman for flying a non-known-ice airplane in forecast icing conditions except when an
While I'm not prepared to accept the NTSB's guidance on ice flying, it is necessary to
establish some basic rules. For example, I have no reservations about descending through
an icing layer at my destination, especially if it's above freezing at the surface. On the
other hand, a departure that requires me to climb through an icing layer gives me
considerable pause. I have to be darned sure that I can get on-top without picking up much
ice before tackling such a departure. This is one of the few situations where a twin has a
big advantage over a single, because although twins don't cruise significantly faster than
singles, they do have a lot more climb capability.
The scariest ice experience I ever had occurred in the winter of
1970 while I was heading home to California from Minneapolis in my Skylane. I wound up
getting stuck in Rapid City, S.D., for several days while I waited out a big snowstorm.
Finally, the snow stopped and I headed out to the airport and went to the FSS for
in-person briefing. I asked about icing PIREPs, and the briefer told me about a Cessna 150
that was practicing holding patterns at 6,000' and reporting only occasional light rime
ice. He also said that a United 737 was due in shortly and might be able to provide
information on tops and icing.
The United flight landed as advertised, and as soon as the last passenger deplaned, I
ran up the airstair, headed for the cockpit, and asked the first officer if he could give
me an in-person PIREP. He replied that the tops were about 12,000 and that he hadn't
noticed any icing during the descent into Rapid City.
"It's essential to take immediate action at the first sign of
icing. Don't just sit there in denial... do something!"
Armed with that information, I returned to the FSS, filed an IFR flight plan westbound,
and launched into the soup. Although it was below freezing on the surface that day, I
experienced no icing during the climb until passing about 7,000' at which point I started
picking up a little. By the time I reached 8,000' I realized my rate of climb had gone to
zero and the engine was starting to lose power. The only way I could restore power was to
use full carburator heat. It became clear that there was no way I was going to be able to
I advised Center that I was picking up moderate ice, couldn't maintain altitude, and
needed to return to Rapid City. The controller gave me a clearance to return and descend.
By the time I reached the outer marker, I realized that my windshield was totally iced
over and completely opaque. The defroster managed to clear only a dime-sized hole right
above the hot air outlet. I wound up shooting the ILS and feeling for the runway. The
landing was a little "firmer" than usual, and the impact caused a large quantity
of ice to fall off the airplane.
Upon taxiing in and shutting down, I discovered that there was 3/4-inch of ice on the
wing leading edges and wing struts, and that the induction air filter was completely iced
over. I pulled a foot-long piece of ice from the wing and plunked on the FSS counter,
saying "here's my pilot report". I then checked back into the motel, at which
point my knees went weak when I realized just how close I'd come to getting in serious
Could I have made this flight successfully had I been flying a known-ice-equipped Turbo
310 instead of a Skylane? Maybe, but maybe not. I'm sure I could have climbed higher than
8,000' in the T310R, but whether I could have made it to on-top is unknowable. If not, the
windshield hot-plate would have come in handy when landing back at Rapid City!
I learned several things from that close call:
No matter how thoroughly you brief, you can never be sure about icing until you fly it.
Trying to climb through an icing layer in a light plane is sometimes impossible.
Most important, it's essential to take immediate action at the first sign of icing.
(I also learned that a Skylane can haul quite a load of ice without falling out of the
sky. I hate to think of what would have happened had I been flying a Mooney!)
The same time-is-of-the-essence attitude is important when ice is encountered enroute. Don't
just sit there in denial...do something! There are three possible ways to escape from
an icing encounter:
Climb (if you think you can get on-top)
Descend (if you think you can get below the freezing level)
Make a 180 and retreat
If you can't decide whether to climb or descend, try climbing first because you
can always descend later (but necessarily not vice-versa). A turbocharger often makes
climbing the preferred option: if you can't climb to on-top, you still may be able to
climb into cold enough temperatures that icing is no longer possible. (Icing rarely occurs
As soon as you've resolved your immediate icing problem, be sure to file a PIREP so
that other pilots can benefit from your knowledge. It's even more important to file PIREPs
when you find that there's no ice despite the forecast. If you think about it, reports of
ice-free altitudes are precisely the sort of thing that other pilots need to know about.
While ice can be penetrated (in limited quantities),
thunderstorms cannot. Whether we're flying a Skyhawk or Citation or Boeing, we have to
steer clear of convective cells. To do this, we must depend on our weather-avoidance
equipment: weather radar, sferics detector (Stormscope or Strikefinder), or Mark I
I've flown with both radar and sferics. I prefer sferics for enroute weather avoidance
(because it sees further and detects turbulence better), and radar for close-in avoidance
during the departure or arrival phase (because it provides accurate distance information).
Having both radar and sferics is even better.
I have a strong preference for avoidance-by-eyeball and use it whenever possible. A
good look at a towering cumulus cloud can tell you a lot more about what's going on than
any electronic box. If you're flying a turbo, climbing up to the low Flight Levels can
really help. Although you usually can't climb above the CB tops, it's often possible to
get a good look at them at FL200 and hopefully circumnavigate them. But eyeball avoidance
has some serious limitations: it's useless with embedded thunderstorms, and it doesn't
work very well after dark.
your airplane is equipped with radar, do yourself a favor and take a good radar course.
Weather radar requires considerable interpretation, and most pilots don't have the
training required to use it effectively. Both Dave Gwinn and Archie Trammel offer excellent weather radar
courses at numerous locations around the country. Archie Trammel's course is also available on
In the absence of airborne weather radar, it's tempting to ask ATC for vectors around
weather. But in my experience, this is risky business because many ATC radar sites aren't
very good a painting weather, and most controllers have little or no training in
interpreting weather returns. I remember flying into Boston Logan in my Skylane many years
ago. New England was awash with convective activity, and the Boston Center controller was
doing his level best to vector me around the worst of the weather. But despite the
controller's good intentions, he wound up vectoring me right through the middle of a
couple of cells. Frankly, it scared the hell out of me.
My 310 is equipped with an old WX-10 Stormscope, and over the years I've learned to
trust it. I've never blundered into serious turbulence when following the Stormscope. When
given the choice of an airborne Stormscope or ATC radar, I'll take the Stormscope every
I recall a trip several years ago when I was flying from New Hampshire to Pennsylvania.
A line of thunderstorms cut across upstate New York. The Stormscope was lit up like a
Christmas tree, but there seemed to be a decent-sized gap in the dots. I advised Albany
Approach that I needed to make a turn to penetrate the weather where the Stormscope showed
a "soft spot". The controller told me that according to his radar, my requested
heading would take me straight into the worst part of the weather.
I decided to trust the Stormscope, despite the controller's increasingly panicky
admonitions. I soon entered the clouds. Then it started to rain, and the rain got
progressively heavier. Yet the Stormscope continued to indicate that there were no dots
stright ahead. The controller called me every couple of minutes to make sure I was okay;
he was clearly frightened that I would get in trouble and he'd have a lot of extra
paperwork to do. After about 15 minutes of this, the rain stopped and I flew into the
clear. I advised the controller that I'd encountered heavy rain but absolutely no
turbulence. He was clearly surprised (and relieved).
This episode serves to underscore the difference
between radar and sferics. Radar detects water, while sferics detects electrical
discharges. Electrical discharges invariably mean that there are strong updrafts and
downdrafts, but water doesn't necessarily mean turbulence. Ground-based weather radar is
designed to measure cloud tops, and airborne weather radar can do the same thing if the
pilot knows his stuff (and is handy with the tilt control). But ATC radar offers no
information on tops, so the controller can tell you about rain but not necessarily
Using a Stormscope effectively requires interpretation, although not as much as
airborne weather radar does. I've found that one of the keys to Stormscope use is the
frequent use of the "clear" button. Although clusters of dots on the screen
usually depict convective activity, the best way to assess storm intensity is to clear the
display and see how fast the dots reappear. The faster the dots appear, the stronger the
Another important lesson is that sferics equipment provides quite accurate direction
information but only a vague idea of distance. A cluster of dots on the Stormscope display
at the 50-mile range ring might not mean the cell is 50 miles away. If it's a weak storm,
it might be a closer than that; if it's unusually strong, it might be a good deal further
way. Often, a single cell will produce electrical discharges of various intensities that
result in dots on the screen at various ranges; this is known as "radial
spread." Although the latest Series II Stormscopes employ software tricks to reduce
radial spread, it exists in some measure with all sferics devices.
The only rule about weather flying is that there are no hard-and-fast rules. That's why
judgment and experience are required. Here's a quick review of some strategies I use:
I consider the human factors affecting me and my passengers before
making a go/no-go decision. Even if my aircraft can handle the weather, maybe its
Before any long trip, I get the big picture by keeping an eye on The
Weather Channel or some of the better Internet sites for a few days before I depart.
I get the best preflight briefing possible, of course, but I temper it
with the knowledge that aviation forecasts often paint a picture worse than what I'll
actually encounter, but also that some weather hazards like icing cannot be forecast with
any real accuracy.
While enroute, I stay tuned in to all available sources of in-flight weather
information, including real-time PIREPs and hourly updates from Flight Watch.
I seldom let an icing forecast discourage me from flying (icing PIREPs
are another matter!), but I take immediate steps to get out of ice when I encounter it,
then file a PIREP for the next guy.
When faced with thunderstorms, I use all available methods to
circumnavigate them: weather radar, sferics gear, and especially my eyes. But I've learned
to be skeptical of weather-avoidance vectors from ATC.
Most important, after obtaining all available weather information, I listen closely to
"that little voice" that tells me whether or not it's okay to go. Call it
"gut feeling" or "the voice of experience" if you prefer. Whatever you
call it, so far it hasn't let me down.